指针数学与数组索引 [英] Pointer math vs. Array index

问题描述

我知道这已经散列过一些时间，但我今天跟我握了握指针运算/数组索引的了解所遇到的情况。

I know this has been hashed over a number of time, but I have come across a case today that shook my understanding of the pointer math/ array index.

正如我永诺理解，和放大器; mybuff [10]和（安培; mybuff + 10）referancing相同的内存equivilent方式。

As I have allways understood it, &mybuff[10] and (&mybuff+10) are equivilent ways of referancing the same memory.

不过，我花了一上午的战斗，其中一个案例：

However I spent the morning fighting a case where:

memcpy(&mybuff+10,&in,8); 

溢出缓冲区，当与优化的编译工作只是罚款编译调试时。

overflowed the buffer, when compiled with optimization on and worked just fine when compiled for debugging.

虽然athe同时

memcpy(&mybuff[10],&in,8); 

在这两种情况下工作得很好。

worked just fine in both cases.

有任何意见或指针非常感谢。

Many thanks for any ideas or pointers.

推荐答案

http://cplusplus.com/doc/tutorial对于运营商的优先顺序/运营/

＆放大器; mybuff + 10 如（安培; mybuff）+10

＆放大器; mybuff [10] 如及（mybuff [10]）

see http://cplusplus.com/doc/tutorial/operators/ for priority order of operators
&mybuff+10 like (&mybuff)+10
&mybuff[10] like &(mybuff[10])

修改

还有一些指针<一href=\"http://cplusplus.com/doc/tutorial/pointers/\">http://cplusplus.com/doc/tutorial/pointers/

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